The National GPS Network

The Global Positioning System (GPS) user in Great Britain, using the free services provided , can obtain precise coordinates in the European standard GPS coordinate system ETRS89, and instantly convert these to British National Grid and heights above mean sea level (Newlyn datum) using Ordnance Survey national standard high-precision transformation models. Surveyors and GIS developers can convert 2D and 3D spatial datasets from GPS coordinates to Ordnance Survey coordinates and vice-versa, with high accuracy.

National GPS Network

SV Surveying Ltd uses Leica GPS System 530 and has experienced surveyors who are able to make use of this technology. We are therefore able to integrate its use into your project large or small at a cost that is realistic and economic.

Coordinate Systems

ETRS89
(European Terrestrial Reference System 1989)

This is our national coordinate system for 3D GPS positioning. It is a much more exacting definition of the GPS coordinate system than the better known WGS84 standard. Consequently, ETRS89 coordinates are also WGS84 coordinates, but be aware that general WGS84 coordinates do not necessarily meet the ETRS89 standard. ETRS89 is the GPS coordinate system standard used for high-quality GPS surveys throughout Europe.

OSGB36 National Grid
(Ordnance Survey Great Britain 1936) 		This is our national coordinate system for topographic mapping. It is used for Ordnance Survey mapping at all scales, and for many private topographic surveys.

The OSGB36 part of the name refers to the geodetic datum (system of latitude and longitude) used, and the National Grid part refers to the map projection and grid referencing convention for eastings and northings.
ODN
(Ordnance Datum Newlyn) 		This is our national coordinate system for heights above mean sea level (orthometric heights). It was originally based on tide gauge readings at Newlyn, Cornwall. ODN is the usual definition of height above mean sea level in mainland Britain and some islands.
 
Ordnance Survey is fully adopting GPS positioning as the basis of all three national coordinate systems listed above.  So in the future, OSGB36 National Grid will not be realised by triangulation stations, and ODN will not be realised by levelled bench marks - both will be realised by GPS positioning. All surveyors who want to take advantage of the new infrastructure will therefore need access to survey-grade GPS equipment.

SV Surveying Ltd uses Leica GPS System 530 and has experienced surveyors who are able to make use of this technology. We are therefore able to integrate its use into your project large or small at a cost that is realistic and economic.

 

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